In so many and such important ways, then, do the planets bear witness to the earth's mobility.

So, influenced by these advisors and this hope, I have at length allowed my friends to publish the work, as they had long besought me to do.

The earth together with its surrounding waters must in fact have such a shape as its shadow reveals, for it eclipses the moon with the arc of a perfect circle.

The earth together with its surrounding waters must in fact have such a shape as its shadow reveals, for it eclipses the moon with the arc of a perfect circle.

For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study.

To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.

Therefore, when I considered this carefully, the contempt which I had to fear because of the novelty and apparent absurdity of my view, nearly induced me to abandon utterly the work I had begun.